This document provides an overview of the mental status examination, a key part of psychiatric evaluation. It describes that the mental status exam involves direct observation of the patient to assess symptoms that are important for diagnosis. It outlines several areas that should be observed, including appearance, behavior, speech, thought processes, thought content, perceptions, mood and affect, insight and judgment, and cognitive functioning. For each area, it provides details on what to look for and definitions of important clinical terms. The mental status exam is important as psychiatric diagnoses are based largely on observations of the patient.